This invention relates to an ID (i.e., identification) registration method and an ID collation system incorporated in a vehicle control system, embodied as a pneumatic tire pressure monitoring apparatus associated with pneumatic pressure sensors. More specifically, the present invention relates to a pneumatic tire pressure monitoring system monitoring the pneumatic pressure of a tire, an electronic key system performing contactless lock/unlock of a door, and a vehicle security control system controlling the pneumatic tire pressure monitoring system and the electronic key system.
A conventional pneumatic tire pressure monitoring system is, for example, disclosed in Japanese Patent No. 3212311 corresponding to U.S. Pat. No. 5,602,524.
According to this kind of conventional pneumatic tire pressure monitoring system, a pneumatic pressure sensor equipped with a transmitter is attached to each tire. The pneumatic pressure sensor transmits an air-pressure detection signal together with an ID assigned to this sensor. A pneumatic tire pressure monitoring apparatus installed in a vehicle body receives the air-pressure detection signal. When any abnormal tire having a lower air pressure is detected, a warning indicator is turned on.
In this case, each sensor ID is also registered in the pneumatic tire pressure monitoring apparatus, so that the monitoring apparatus can check whether or not the received air-pressure signal is transmitted from the tire of its own vehicle.
According to the above conventional system, the sensor ID is assigned to each sensor at the shipment or delivery stage of this sensor from a sensor maker. Then, this sensor is installed into a designated vehicle in an automobile maker. In this assembling process, the pneumatic tire pressure monitoring apparatus installed in a vehicle body is switched into an ID registration mode so that the ID transmitted from the sensor can be received by the monitoring apparatus and the received ID can be registered in the monitoring apparatus.
More specifically, as shown in FIG. 20, the conventional pneumatic tire pressure monitoring system includes a plurality of pneumatic pressure sensors 110, 120, 130, and 140 attached to respective tires and a pneumatic tire pressure monitoring apparatus 150 installed in a vehicle body. The pneumatic pressure sensor 110 includes an air pressure sensor 111 detecting the air pressure of a tire, an ID memory 112 storing a registered sensor ID, a transmitting circuit 113, a power source battery 114, a control unit 115, and a transmitting antenna 116. Other pneumatic pressure sensors 120, 130, and 140 are identical in arrangement with the sensor 110.
The pneumatic tire pressure monitoring apparatus 150 includes a receiving circuit 151, a receiving antenna 152, a power source circuit 153, a control unit 154, a memory 155, and a communication circuit 156. The communication circuit 156 is connected via a signal line to a display unit 160 such as an indicator or LED to transmit display data to the display unit 160. A vehicle battery 170, supplying electric power, is connected to the pneumatic tire pressure monitoring apparatus 150. A mode changing switch 180 is provided to switch the operation of the control unit 154 between an ordinary mode and an ID registration mode.
The ID registration is performed in an automobile manufacturing line in accordance with a procedure shown in FIG. 21. First of all, the pneumatic tire pressure monitoring apparatus 150 is switched into an ID registration mode (step S5110). Next, respective pneumatic pressure sensors 110, 120, 130, and 140 transmit their sensor IDs stored in their ID memories (step S5120) into the air. The pneumatic tire pressure monitoring apparatus 150 receives the sensor IDs via the receiving antenna 152 (step S5130). Then, the control unit 154 of the pneumatic tire pressure monitoring apparatus 150 makes a judgment as to whether or not the received signal has a level equal to or larger than a reference level (step S5140). When the received signal level is not smaller than the reference level (i.e., YES in step S5140), the sensor ID included in the received signal is registered in the memory 155 of the pneumatic tire pressure monitoring apparatus 150 (step S5150). Then, the control unit 154 makes a judgment as to whether or not the registration of the sensor IDs of respective sensors 110, 120, 130, and 140 has been accomplished (step S5160). When the ID registration for respective sensors 110, 120, 130, and 140 is already accomplished (YES in step S5160), the mode changing switch 180 is switched to return the monitoring apparatus 150 to the ordinary mode (step S5170).
In this manner, according to the conventional system, the sensor ID of the pneumatic pressure sensor actually attached to each tire of a vehicle is registered in the monitoring apparatus. In the ordinary mode, the monitoring apparatus checks whether or not the ID contained in each signal received through the receiving antenna 152 agrees with a collation ID stored in the memory 155. When the agreement is recognized, the air-pressure condition of the tire is judged based on a received pressure signal. Display of the display unit 160 is performed based on the judgment result. Registering the collation ID as described above is effective in preventing erroneous display performed based on a signal transmitted from a pneumatic pressure sensor attached to a tire of any other vehicle traveling or stopping nearby.
However, many vehicles are successively conveyed on the same assembling line at short intervals of time. Performing the registration of collation ID in such a congested condition will be possibly subjected to the problem of interference occurring in radio data transmission, according to which the monitoring apparatus of a vehicle may erroneously receive the ID signal sent from a pneumatic pressure sensor of a neighboring vehicle. The similar problem occurs in a repair shop in which the re-registering operation of the collation ID is performed.
Furthermore, electronic keys are recently used for controlling automotive vehicles by performing radio or wireless communication between the electronic key and an automotive security control computer (i.e., security ECU). For example, the electronic key allows a user to open or close an automotive door without inserting the key into a key cylinder. Furthermore, it is known that the electronic key can be used to start the engine before the user enters into the car. According to such an electronic key system, a key ID of the authorized electronic key is registered in the security ECU. Then, the security ECU performs ID collection with reference to the registered key ID when communicating with the electronic key. Thus, even in such an electronic key system, it is necessary to eliminate erroneous ID registration.
The employment of such an electronic key system is not limited to automotive vehicles. For example, a similar key system can be applied to an entrance door of a house in which a security computer is installed. Even in such a housing security system, the ID collation is performed with reference to ID information registered beforehand for an authorized key.